Ultraviolet and infrared radiation absorbing glass

ABSTRACT

An ultraviolet and infrared radiation absorbing glass is disclosed, which has a bronze or neutral gray tint, a low ultraviolet transmission, and a low total solar energy transmission and is suitable for use as a window glass for motor vehicles or buildings. The glass comprises, in % by weight: basic glass components comprising 65 to 80% SiO 2 , 0 to 5% B 2 O 3 , 0 to 5% Al 2 O 3 , 0 to 10% MgO, 5 to 15% CaO, 10 to 18% Na 2 O, and 0 to 5% K 2 O, provided that the sum of MgO and CaO is 5 to 15% and the sum of Na 2 O and K 2 O is 10 to 20%; coloring components comprising 0.20 to 0.30% total iron oxide (T-Fe 2 O 3 ) in terms of Fe 2 O 3 , 0.65 to 1.1% CeO 2 , 0.35 to 1.1% TiO 2 , 0.001 to 0.005% CoO, and 0.0003 to 0.0015% Se; and an additional component comprising 0.02 to 0.30% SO 3 , wherein 20.5 to 25% of said T-Fe 2 O 3  is FeO in terms of Fe 2 O 3 .

TECHNICAL FIELD

The present invention relates to an ultraviolet and infrared radiationabsorbing glass having a bronze or neutral gray tint.

TECHNICAL BACKGROUND

In order to meet the demand for protection of interior trim ofautomobiles against deterioration, which has been increasing with therecent trend to luxury of the interior trim, and to reduce the load ofair conditioning, a glass having ultraviolet and infrared radiationabsorbing power has recently been proposed as an automotive windowglass.

For example, a green tinted glass containing a relatively large amountof Fe₂O₃ and having enhanced heat radiation and ultraviolet radiationabsorbing power has been developed for automotive use.

In glasses having a bronze or brown tint, the ultraviolet radiationabsorbing power thereof is enhanced by using CeO₂ and TiO₂ at a lowerFe₂O₃ content than the green tinted glass. For example, the heatradiation absorbing glass having a bronze tint disclosed in JP-A-6-40741(the term “JP-A” as use herein means an “unexamined published Japanesepatent, application”) comprises, in % by weight, basic glass componentscomprising 68 to 74% SiO₂, 0.1 to 3% Al₂O₃, 2 to 4.5% MgO, 8 to 11% CaO,11.5 to 16% Na₂O, 0.5 to 3.0% K₂O, and 0.1 to 0.4% SO₃, provided thatthe sum of SiO₂ and Al₂O₃ is 68 to 74%, the sum of CaO and MgO is 11 to15%, and the sum of Na₂O and K₂O is 12 to 17%, and coloring componentscomprising 0.13 to 0.55% total iron oxide in terms of Fe₂O₃, 0.2 to 0.6%CeO₂, and 0.15 to 0.45% TiO₂, and further comprises 0.3 to 14 ppm CoOand 5 to 20 ppm Se. This glass has a reduction rate (Fe²⁺/Fe³⁺) of 17 to55%.

The ultraviolet radiation absorbing colored glass disclosed inJP-A-6-345482 is a brown tinted glass which comprises, in % by weight,65 to 75% SiO₂, 0.1 to 5% Al₂O₃, 1 to 6% MgO, 5 to 15% CaO, 10 to 18%Na₂O, 0 to 5% K₂O, 0.05 to 1.0SO₃, 0.2 to 1.5% CeO₂, 0 to 1.0% TiO₂, 0to 0.0015% CoO, 0.0002 to 0.0012% Se, and 0.2 to 0.4% Fe₂O₃, wherein 3to 15% of the total iron oxide in terms of Fe₂O₃ is FeO.

The ultraviolet radiation absorbing colored glass disclosed inJP-A-6-345483 is a glass which comprises, in % by weight, 65 to 75%SiO₂, 0.1 to 5% Al₂O₃, 1 to 6% MgO, 5 to 15% CaO, 10 to 18% Na₂O, 0 to5% K₂O, 0.05 to 1.0% SO₃, 0.4 to 1.0% CeO₂, 0 to 1.0% TiO₂, 0.0018 to0.0030% CoO, 0.0001 to 0.0010% Se, and 0.1 to 0.3% Fe₂O₃, wherein 3 to20% of the total iron oxide in terms of Fe₂O₃ is FeO.

Furthermore, the gray glass composition disclosed in JF-A-8-48540 is acolored glass composition having a dull gray tint which comprises, in %by weight, 66 to 75% SiO₂, 0 to 5% Al₂O₃, 0 to 5% MgO, 5 to 15% CaO, 10to 20% Na₂O, 0 to 5% K₂O, 0.0003 to 0.0050% CoO, 0.0001 to 0.0015% Se,and 0.30 to 0.70% Fe₂O₃ (total iron oxide), with the FeO content beingup to 0.21%, and which may further contain up to 2.0% CeO₂, V₂O₅, TiO₂,and MoO₃.

The above-described conventional ultraviolet and infrared radiationabsorbing glasses have an ultraviolet radiation absorbing power impartedby Fe₂O₃CeO₂, and TiO₂, and by interactions among them. However, in theglasses having a bronze or neutral gray tint obtained by using thecoloration of Se, the Fe₂O₃ content must be reduced to a relatively lowlevel in order to maintain the pink coloration of Se. Consequently, ithas been difficult to achieve both a bronze or neutral gray tint andhigh ultraviolet radiation absorbing power.

That is, there has been the following problems. When the TiO₂ content isincreased, the glass tends to be yellowish. Even when the CeO₂ contentis increased, the coloration of Se is sometimes insufficient dependingon the oxidation and reduction state of the glass, so that theultraviolet radiation absorbing power is not effectively increased.

This kind of glasses further have a drawback that an increase in theproportion of FeO in total iron oxide tends to result in theabove-described problems concerning color tint. In the case of ordinaryglasses having a bronze or neutral gray tint and not having highultraviolet radiation absorbing power, an increase in FeO proportion mayimpair the infrared radiation absorbing power thereof.

The present invention has been made in the light of the above-describedproblems associated with the conventional techniques.

An object of the present invention is to provide an ultraviolet andinfrared radiation absorbing glass having a bronze or neutral gray tintand having especially high ultraviolet radiation absorbing power andsatisfactory infrared radiation absorbing power.

DISCLOSURE OF THE INVENTION

The present invention provides an ultraviolet and infrared radiationabsorbing glass comprising, in % by weight:

basic glass components comprising

65 to 80% SiO₂,

0 to 5% B₂O₃ ,

0 to 5% Al2O₃,

0 to 10% MgO,

5 to 15% CaO,

10 to 18% Na₂O, and

0 to 5% K₂O,

provided that the sum of MgO and CaO is 5 to 15% and the sum of Na₂O andK₂O is 10 to 20%;

coloring components comprising

0.20 to 0.30% total iron oxide (T-Fe₂O₃) in terms of Fe₂O₃,

0.65 to 1.1% CeO₂,

0.35 to 1.1% TiO₂,

0.001 to 0.005% CoO, and

0.0003 to 0.0015% Se; and

an additional component comprising

0.02 to 0.30% SO₃,

wherein 20.5 to 25% of said T-Fe₂O₃ is FeO in terms of Fe₂O₃.

PREFERRED EMBODIMENTS OF THE INVENTION

The ultraviolet and infrared radiation absorbing glass described abovepreferably contains 0.0005 to 0.005% by weight NiO.

The ultraviolet and infrared radiation absorbing glass preferablycontains 0.20 to 0.90% by weight La₂O₃.

The ultraviolet and infrared radiation absorbing glass of the presentinvention preferably has such optical characteristics that the visiblelight transmission as measured with the CIE standard illuminant A of 70%or more and the total solar energy transmission as measured in awavelength region of from 300 to 2,100 nm is less than 72%, when thethickness thereof is from 3.25 to 6.25 mm.

Furthermore, the ultraviolet and infrared radiation absorbing glass ofthe present invention preferably has such optical characteristics thatthe dominant wavelength thereof as measured with the CIE standardilluminant C is 572 to 580 nm and the total sunlight ultraviolettransmission defined in ISO9050 as measured in a wavelength region offrom 297.5 to 377.5 nm is less than 12%, when the glass has a thicknessof 3.25 to 6.25 mm.

The reasons for limitations of the composition of the ultraviolet andinfrared radiation absorbing glass according to the present inventionare explained below. Hereinafter, all percents used for componentamounts are by weight. The composition of the glass is based on a glasscomposition suitable for forming by a float process.

SiO₂ is a main component forming a skeleton of glass. If the SiO₂content is less than 65%, the glass has poor durability. If the SiO2content exceeds 80%, the glass is difficult to melt.

Although B₂O₃, is a component generally used for improving glassdurability or as a melting aid, it also functions to enhance ultravioletabsorption. If the B₂O₃ content exceeds 5%, not only the decrease oftransmission in the ultraviolet region extends to the visible region,often resulting in a yellowish tint, but also troubles arise in glassforming due to vaporization of B₂O₃, etc. Accordingly, the upper limitof the B₂O₃ content should be 5%.

Al203 serves to improve glass durability. If the Al₂O₃ content exceeds5%, the glass is difficult to melt. From the standpoint of obtaining aglass having moderately improved durability while preventing the glassfrom having an elevated melting temperature, the preferred range ofAl₂O₃ content is from 0.1 to 2%.

MgO and CaO both are used for improving glass durability and forregulating a liquidus temperature and viscosity of the glass duringforming. If the MgO content exceeds 10%, the liquidus temperature rises.If the CaO content is less than 5% or higher than 15%, the liquidustemperature rises. If the total content of MgO and CaO is less than 5%,the durability of the resulting glass deteriorates. If the total contentthereof exceeds 15%, the liquidus temperature rises.

Na₂O and K₂O are used as glass melting accelerators. If the Na₂O contentis less than 10% or if the total content of Na₂O and K₂O is less than10%, the effect of melting acceleration is poor. If the Na₂O contentexceeds 18% or if the total content of Na₂O and K₂O exceeds 20%, glassdurability is decreased. K₂O further has the effect of enhancing thepink coloration of Se and, at the same time, increasing the ultravioletradiation absorbing power. It is undesirable to incorporate K₂O in anamount exceeding 5%, because it is more expensive than Na₂O.

Iron oxide in a glass is present in the forms of Fe₂O₃ (Fe³⁺) and FeO(Fe²⁺). FeO is a component which serves to enhance infrared radiationabsorbing power, while Fe₂O₃ is a component which serves to enhanceultraviolet radiation absorbing power together with CeO₂ and TiO₂.

If the amount of the total iron oxide (T-Fe₂O₃) is too small, theinfrared radiation absorbing power and ultraviolet radiation absorbingpower are low. If the amount thereof is too large, the visible lighttransmission is decreased. Therefore, the preferred range of the totaliron oxide content is from 0.20 to 0.30%.

If the amount of FeO is too small, the infrared radiation absorbingpower is decreased. If the amount thereof is too large, the visiblelight transmission is decreased. Therefore, the preferred range of FeOamount in terms of Fe₂O₃ is from 20.5 to 25% of the total iron oxide.

In the present invention, a relatively low total iron oxide content anda relatively high FeO content are employed mainly for the purpose ofenhancing the infrared radiation absorbing power while maintaining ahigh visible light transmission. Those ranges of total iron oxidecontent and FeO content are suitable for this purpose.

CeO₂, which is an essential component in the present invention, servesto enhance ultraviolet radiation absorbing power. CeO₂ in a glass ispresent in the form of Ce³⁺ or Ce⁴⁺. In particular, Ce³⁺ shows reducedabsorption in the visible light region and is effective in ultravioletabsorption. If the CeO₂ content is too high, the glass shows enhancedabsorption in a shorter-wavelength part of the visible light region andis hence yellowish. In addition, since the cerium oxide used as a rawmaterial serves as an oxidizing agent, it is difficult to maintain ahigh FeO/T-Fe₂O₃ ratio when a glass having a high CeO₂ content ismelted. Therefore, the CeO₂ content is preferably from 0.65 to 1.1%.

TiO₂, which is an essential component in the present invention, servesto enhance ultraviolet radiation absorbing power particularly by theinteraction with FeO. If the TiO₂ content is too high, the glass tendsto be yellowish. In the present invention, a high FeO/T-Fe₂O₃ ratio isused with a small total iron oxide amount and, in order to facilitatereduced melting necessary for attaining the FeO/T-Fe₂O₃ ratio, arelatively small CeO₂ amount in the range of from 0.65 to 1.1% is used,as stated above. Therefore, from the standpoint of compensating for theresultant insufficiency of ultraviolet radiation absorbing power, theTiO₂ content is preferably from 0.35 to 1.1%.

CoO is a component for forming a bronze or neutral gray tint by thecoexistence thereof with Se. If the CoO content is less than 0.001%, thedesired tint cannot be obtained. If the CoO content exceeds 0.005%, thevisible light transmission is decreased.

Se is a component for obtaining a bronze or neutral gray tint due to itspink coloration in combination with the complementary color of CoO. Ifthe Se content is less then 0.0003%, the desired tint cannot beobtained. If the Se content exceeds 0.0015%, the visible lighttransmission is decreased.

SO₃ is a component which has come into the glass mainly from a sulfuricacid salt or the like used as a refining agent. In order to obtain anFeO/T-Fe₂O₃ ratio in the range specified above, the amount of a sulfuricacid salt, e.g., salt cake, is regulated so as to result in an SO₃content in the glass of from 0.02 to 0.30%. If the SO₃ content is lessthan 0.02%, refining is insufficient. If the SO₃ content exceeds 0.30%,the coloration of Se is weakened disadvantageously.

NiO is a component for obtaining a neutral gray tint. If the NiO contentis too high, the visible light transmission is decreased. Therefore, itshould be used in an amount of 0.005% or less.

La₂O₃ not only is effective in decreasing the viscosity of the moltenglass and accelerating glass melting, but also improves the chemicaldurability of the glass, such as water resistance. The addition of La₂O₃to a glass containing Fe₂O₃ and CeO₂ is also effective in decreasing theultraviolet transmission. If the La₂O₃ content is less than 0.20%, thoseeffects are insufficient. Since La₂O₃ is an expensive raw material, thecontent thereof is preferably not higher than 0.90%. La₂O₃ may be addedin the form of a raw material containing La₂O₃ in a high concentration.However, such a raw material is costly because it needs to be refined.From the standpoint of attaining a decreased raw-material cost, it istherefore preferred to add La₂O₃ in the form of a mixture of La₂O₃ andCeO₂ occurring simultaneously, without separating these, or in the formof an impurity remaining in CeO₂ having a low degree of purification. Inthe latter case, oxides of other rare earth elements, such as Pr₂O₃ andNd₂O₃, also come as impurities into the glass in slight amounts.However, such impurities may be contained as long as this is not counterto the spirit of the invention.

The glass having the above-described composition of the presentinvention may further contain at least one of ZnO, MnO, V₂O₅, and MoO₃in a total amount of 0 to 1%, as long as these ingredients are notcounter to the spirit of the invention.

Of those optional ingredients, ZnO, which is apt to generate upon glassmelting in a reducing atmosphere, is effective in preventing theformation of nickel sulfide causative of spontaneous fracture of aglass.

MnO, V₂O₅, and MoO₃ in the glass each serves as an ultraviolet absorbingcomponent. These components can be used according to their degrees ofultraviolet absorption for the fine control of a bronze or neutral graytint.

The present invention will be described in more detail by reference tothe following Examples. It should however he understood that theinvention is not construed as being limited thereto.

EXAMPLES

In order to obtain given glass compositions, ingredients were suitablymixed which consisted of silica sand, dolomite, limestone, soda ash,potassium carbonate, boron oxide, salt cake, ferric oxide, titaniumoxide, cerium oxide, cobalt oxide, sodium selenite, nickel oxide,lanthanum oxide, and a carbonaceous material as a reducing agent. Theresulting raw materials each was melted at 1,500° C. for 4 hours in anelectric furnace. Each molten glass was then cast on a stainless-steelplate and annealed to obtain a glass plate having a thickness of about 7mm. The glass plates obtained were polished so as to have thicknesses of3.5, 4, and 5 mm. Optical characteristics of the samples thus obtainedwere measured. The optical characteristics included visible lighttransmission (YA) measured with the CIE standard illuminant A, totalsolar energy transmission (TG), ultraviolet radiation transmission (Tuv)defined in ISO 9050, dominant wavelength (Dw) and excitation purity (Pe)both measured with the CIE standard illuminant C, and L*, a*, and b*defined in CIE.

The results obtained in the Examples are shown in Tables 1 to 5, whichshow the concentration of each component in each sample obtained and thevalues of optical characteristics for each sample. All values ofconcentration given in the Tables are % by weight, and the values of theratio of FeO in terms of Fe₂O₃ to T-Fe₂O₃ are also given in %.

TABLE 1 Example 1 Example 2 Example 3 Composition (wt %) SiO₂ 70.6 70.770.9 B₂O₃ — — — Al₂O₃ 1.4 1.4 1.4 MgO 4.0 4.0 4.0 CaO 8.0 8.0 8.0 Na₂O13.0 13.0 13.0 K₂O 0.7 0.7 0.7 Se 0.0011 0.0009 0.0011 CoO 0.0020 0.00250.0025 CeO₂ 1.00 1.10 0.85 TiO₂ 1.00 0.90 0.90 NiO — — — La₂O₃ — — —T-Fe₂O₃ 0.27 0.23 0.25 FeO 0.057 0.050 0.050 FeO/T-Fe₂O₃ (%) 23.3 24.122.4 SO₃ 0.05 0.07 0.08 Optical Characteristics Thickness (mm) 3.5 3.53.5 YA (%) 73.5 74.0 74.0 TG (%) 67.8 69.8 69.8 L⁺ 88.4 88.6 88.7 a⁺−0.88 −0.74 −0.83 b⁺ 7.02 6.50 4.50 λd 574 576 573 Pe (%) 7.10 6.30 4.49Tuv (%) 9.2 10.3 11.9

TABLE 2 Example 4 Example 5 Example 6 Composition (wt %) SiO₂ 70.9 70.870.8 B₂O₃ — — — Al₂O₃ 1.4 1.6 1.6 MgO 4.0 4.0 4.0 CaO 8.0 8.0 8.0 Na₂O13.0 13.0 13.0 K₂O 0.7 0.8 0.8 Se 0.0011 0.0011 0.0011 CoO 0.0025 0.00200.0020 CeO₂ 0.85 0.85 0.85 TiO₂ 0.90 0.70 0.70 NiO — — — La₂O₃ — — —T-Fe₂O₃ 0.25 0.25 0.25 FeO 0.047 0.056 0.046 FeO/T-Fe₂O₃ (%) 20.7 24.820.5 SO₃ 0.09 0.05 0.09 Optical Characteristics Thickness (mm) 3.5 4.04.0 YA (%) 74.2 72.7 74.0 TG (%) 70.7 66.8 69.3 L⁺ 88.5 88.0 88.1 a⁺−0.70 −0.73 −0.36 b⁺ 4.92 5.96 5.78 λd 576 575 576 Pe (%) 5.05 6.18 5.91Tuv (%) 11.4 11.4 11.4

TABLE 3 Example 7 Example 8 Example 9 Example 10 Composition (wt %) SiO₂71.0 70.6 71.4 70.0 B₂O₃ — — — 2.0 Al₂O₃ 1.6 1.6 1.6 1.4 MgO 4.0 4.0 4.03.9 CaO 8.0 8.0 8.0 8.0 Na₂O 13.0 13.0 13.0 12.8 K₂O 0.8 0.8 0.8 0.7 Se0.0011 0.0009 0.0007 0.0007 CoO 0.0015 0.0027 0.0012 0.0012 CeO₂ 0.850.70 0.65 0.65 TiO₂ 0.50 1.10 0.35 0.35 NiO — — — — La₂O₃ — — — —T-Fe₂O₃ 0.25 0.25 0.25 0.25 FeO 0.047 0.048 0.055 0.054 FeO/T-Fe₂O₃ (%)20.7 21.3 24.4 24.0 SO₃ 0.09 0.09 0.07 0.07 Optical CharacteristicsThickness (mm) 5.0 4.0 5.0 4.0 YA (%) 72.0 71.9 72.2 73.4 TG (%) 65.867.6 65.1 67.1 L⁺ 87.6 87.4 87.7 88.2 a⁺ −0.45 −0.51 −0.24 −0.31 b⁺ 6.616.33 4.67 5.26 λd 576 576 576 576 Pe (%) 6.93 6.62 5.52 5.35 Tuv (%)10.2 10.3 11.9 10.3

TABLE 4 Example Example Example Example 11 12 13 14 Composition (wt %)SiO₂ 71.0 71.1 70.6 70.7 B₂O₃ — — — — Al₂O₃ 1.4 1.4 1.8 2.0 MgO 4.0 4.04.0 4.0 CaO 8.0 8.0 8.0 8.0 Na₂O 13.0 13.0 13.0 13.0 K₂O 0.7 0.7 1.0 1.1Se 0.0008 0.0006 0.0011 0.0008 CoO 0.0035 0.0018 0.0015 0.0011 CeO₂ 0.650.65 0.85 0.65 TiO₂ 1.10 0.90 0.50 0.35 NiO — — 0.0010 0.0020 La₂O₃ — —— — T-Fe₂O₃ 0.20 0.30 0.25 0.25 FeO 0.045 0.056 0.049 0.049 FeO/T-Fe₂O₃(%) 25.0 20.7 21.8 21.8 SO₃ 0.06 0.10 0.08 0.08 Optical CharacteristicsThickness (mm) 5.0 3.5 5.0 5.0 YA (%) 72.2 73.3 71.5 71.5 TG (%) 66.168.0 65.1 64.9 L⁺ 87.9 88.5 87.8 87.7 a⁺ −0.43 −0.42 −0.39 −0.17 b⁺ 5.156.52 6.97 5.21 λd 576 576 576 576 Pe (%) 6.11 6.70 6.91 5.40 Tuv (%) 9.911.8 9.8 11.9

TABLE 5 Example 15 Example 16 Example 17 Composition (wt %) SiO₂ 70.070.6 71.1 B₂O₃ — — — Al₂O₃ 1.4 1.4 1.6 MgO 4.0 4.0 4.0 CaO 8.0 8.0 8.0Na₂O 13.0 13.0 13.0 K₂O 0.7 0.7 0.8 Se 0.0009 0.0011 0.0009 CoO 0.00250.0020 0.0012 CeO₂ 1.10 0.85 0.65 TiO₂ 0.90 0.70 0.35 NiO — — — La₂O₃0.70 0.51 0.30 T-Fe₂O₃ 0.25 0.25 0.24 FeO 0.051 0.053 0.052 FeO/T-Fe₂O₃(%) 22.6 23.5 24.1 SO₃ 0.08 0.07 0.06 Optical Characteristics Thickness(mm) 3.5 4.0 5.0 YA (%) 74.0 72.7 74.1 TG (%) 69.8 66.8 65.0 L⁺ 88.688.0 88.7 a⁺ −0.74 −0.73 −0.23 b⁺ 6.50 5.96 4.82 λd 576 575 576 Pe (%)6.30 6.18 5.03 Tuv (%) 10.3 11.4 11.9

The samples obtained in Examples 1 to 12, shown in Tables 1 to 4, eachwas within the scope of claim 1. Specifically, each sample had acomposition which contained

0.20 to 0.30% total iron oxide in terms of Fe₂O₃,

0.65 to 1.1% CeO₂,

0.35 to 1.1% TiO₂,

0.001 to 0.005% CoO,

0.0003 to 0.0015% Se, and

0.02 to 0.30% SO₃

and in which the proportion of FeO in terms of Fe₂O₃ to T-Fe₂O₃ was from20.5 to 25%.

Of the samples obtained in the above Examples, the sample of Example 10was a glass containing 2% B₂O₃ so as to have a reduced ultraviolettransmission and improved glass durability.

The samples obtained in Examples 13 and 14, which were within the scopeof the preferred embodiment, contained NiO so as to have a controlledtint.

The samples obtained in Examples 15 to 17, which were within the scopeof the further preferred embodiment, contained La₂O₃ so as to have areduced ultraviolet transmission and improved chemical durability.

The samples obtained in the Examples each was a bronze or neutralgray-tinted ultraviolet and infrared radiation absorbing glass having avisible light transmission as measured with the CIE standard illuminantA of 70% or more, a total solar energy transmission of less than 72%, adominant wavelength and an excitation purity as measured with the CIEstandard illuminant C of 572 to 580 nm and less than 8%, respectively,and an ultraviolet transmission defined in ISO 9050 of less than 12%.

COMPARATIVE EXAMPLES

Comparative Examples to the present invention are shown in Table 6.

TABLE 6 Comparative Comparative Comparative Example 1 Example 2 Example3 Composition (wt %) SiO₂ 71.8 70.9 70.8 B₂O₃ — — — Al₂O₃ 1.7 1.4 1.6MgO 3.6 4.0 4.0 CaO 7.0 8.0 8.0 Na₂O 13.0 13.0 13.0 K₂O 0.8 0.7 0.8 Se0.0010 0.0008 0.0011 CoO 0.0025 0.0005 0.0020 CeO₂ 0.90 0.41 0.00 TiO₂1.06 0.31 2.00 NiO — — — La₂O₃ — — — T-Fe₂O₃ 0.18 0.40 0.27 FeO 0.0250.079 0.062 FeO/T-Fe₂O₃ (%) 15.6 21.8 25.6 SO₃ 0.09 0.08 0.06 OpticalCharacteristics Thickness (mm) 5.0 4.0 3.5 YA (%) 73.5 73.4 71.5 TG (%)73.0 59.5 66.1 L⁺ 88.2 87.8 87.2 a⁺ 0.23 −0.56 −0.22 b⁺ 4.81 8.56 8.10λd 578 574 577 Pe (%) 5.11 8.40 8.55 Tuv (%) 9.0 16.7 21.4

The sample obtained in Comparative Example 1 was outside the scope ofthe present invention with respect to T-Fe₂O₃ content and FeO/T-Fe₂O₃ratio. This sample had a total solar energy transmission of 72% or more.The sample obtained in Comparative Example 2 was outside the scope ofthe present invention with respect to T-Fe₂O₃, CeO₂, TiO₂, and CoOcontents, while the sample obtained in Comparative Example 3 was outsidethe scope of the present invention with respect to CeO₂ and TiO₂contents and FeO/T-Fe₂O₃ ratio. The samples of Comparative Examples 2and 3 each had an excitation purity of 8% or more and an ultraviolettransmission defined in ISO 9050 of 12% or more. Thus, the glasses ofComparative Examples 1 to 3 each failed to combine a bronze or neutralgray tint, a low total solar energy transmission, and a low ultraviolettransmission.

As apparent from the Examples and Comparative Examples given above, theglass of the present invention is an excellent ultraviolet and infraredradiation absorbing glass which combines a bronze or neutral gray tint,a low ultraviolet transmission, and a low total solar energytransmission.

According to the present invention, an ultraviolet and infraredradiation absorbing glass having enhanced infrared radiation absorbingpower while retaining a high visible light transmission can be obtainedby regulating the total iron oxide content to a value as small as from0.20 to 0.30% and regulating the proportion of FeO in terms of Fe₂O₃ toa relatively large value of from 20.5 to 25% based on the total ironoxide. Furthermore, the glass has been regulated so as to have a CeO₂content of from 0.65 to 1.1% for facilitating reduced melting and have aTiO₂ content of from 0.35 to 1.1% for compensating for insufficiency ofultraviolet radiation absorbing power. Thus, the glass according to thepresent invention is an excellent ultraviolet and infrared radiationabsorbing glass which combines a bronze or neutral gray tint, obtainedby the coloration of Se in combination with that of CoO, a lowultraviolet transmission, and a low total solar energy transmission.

According to the preferred embodiment, a glass tinted with a regulatedbronze or neutral gray tone while retaining the various opticalcharacteristics attained due to the above constitution can be obtainedby incorporating NiO.

According to the further preferred embodiment, a glass having improvedchemical durability and a reduced ultraviolet transmission whileretaining the various optical characteristics attained due to the aboveconstitution can be obtained by incorporating La₂O₃.

POSSIBLE COMMERCIAL USE OF THE INVENTION

As described above in detail, the ultraviolet and infrared radiationabsorbing glass of the present invention makes it possible to produce aglass tinted with a bronze or neutral gray tone and having excellentultraviolet radiation absorbing power.

Furthermore, since the ultraviolet and infrared radiation absorbingglass of the present invention has high ultraviolet radiation absorbingpower and a bronze or neutral gray tint, it is suitable for use as,e.g., a window glass for automobiles and other vehicles and forbuildings. In such applications, the glass of the present invention ishighly effective in, e.g., preventing the interior materials fromdeteriorating or fading.

What is claimed is:
 1. An ultraviolet and infrared radiation absorbingglass comprising, in % by weight: basic glass components comprising 65to 80% SiO₂, 0 to 5% B₂O₃, 0 to 5% Al₂O₃, 0 to 10% MgO, 5 to 15% CaO, 10to 18% Na₂O, and 0 to 5% K₂O, provided that the sum of MgO and CaO is 5to 15% and the sum of Na₂O and K₂O is 10 to 20%; coloring componentscomprising 0.20 to 0.30% total iron oxide (T-Fe₂O₃) in terms of Fe₂O₃,0.65 to 1.1% CeO₂, 0.35 to 1.1% TiO₂, 0.001 to 0.005% CoO, and 0.0003 to0.0015% Se; and an additional component comprising 0.02 to 0.30% SO₃,wherein 20.5 to 25% of said T-Fe₂O₃ is FeO in terms of Fe₂O₃, and saidultraviolet and infrared radiation absorbing glass has a dominantwavelength and an excitation purity, as measured with the CIE standardilluminant C, of 572 to 580 nm and 4.49%-7.10%, respectively, when theglass has a thickness of 3.25 to 6.25 mm.
 2. The ultraviolet andinfrared radiation absorbing glass of claim 1, which further comprises0.0005 to 0.005% by weight NiO.
 3. The ultraviolet and infraredradiation absorbing glass of claim 1 or 2, which further comprises 0.20to 0.90% by weight La₂O₃.
 4. The ultraviolet and infrared radiationabsorbing glass of any one of claims 1 to 2, which has a visible lighttransmission of 70% or more as measured with the CIE standard illuminantA, when the glass has a thickness if 3.25 to 6.25 mm.
 5. The ultravioletand infrared radiation absorbing glass of any one of claims 1 to 2,which has a solar energy transmission of less than 72%, when the glasshas a thickness of 3.25 to 6.25 mm.
 6. The ultraviolet and infraredradiation absorbing glass of any of claims 1 to 2, which has anultraviolet transmission defined in ISO 9050 of less than 12%, when theglass has a thickness of 3.25 to 6.25 mm.